Electric signaling system



June 15 Q1926.

H.ARNDT ELECTRIC SIGNALING SYSTEM Filed August 24, 1925 I 470 employed in I Patented June 15, 1926.

UNITED STATES HEBKANN ARNDT, F BERLIN,

' TIENGESELLSGHAET,

TION OF GERMANY.

OF SIEMENSSTADT, NEAR BERLIN,

GERMANY, .ASSIGNOR '10 SIEMENS & AIK- GERKANY, A CORPORA- ELECTRIC SIGNALING SYSTEM.-

Application filed August 24, 1925, Serial No. 52,032,

My invention relates to electric signaling systems and particularly to improvements in the known signaling systems as used for railroad purposes in which the signals are given by appropriately colored sources. of light so that if a certain track is occupied a red signal appears and if the track is free a green signal.

The object of my invention is to provide means which ensure the highestpossible working safety. In order to attain this end inview it is necessary to avoid that in such systems the'lighting up of the red lamp 'be made dependent upon the closing of a contact.

In practicing my object is attained by red lamps while the green lamps up. When the green lamps are ext'nguished the short-circuiting circuit of the red lamps is opened and the red lamps are lighted up. The lighting up of the red lamps is thus not dependent upon the closing of a contact member. j

The operation of the contact member provided for the opening of the short-circuiting circuit may either'be mechanically coupled with the contact member which interrupts the circuit for the green lamps or it may by 80 electrical means, such ,as a relay, made dependent upon the conditions of the circuit for the green lamps.

invention the above short-circuitin g the In the accompanying drawings attachedto my specification and forming part thereof an embodiment of my invention is illustrated by way of example, Fig. 1 diagrammatically illustrating the general arrangement of the circuits, and Fig. 2 showing a modification Fig. 1. It. has been assume 7 hereby that the lampsiare to be fed by alternating current.

Re erring to these drawings 1 is-the green go ahead lamp which receives current from the transformer 2 through the line 3 and ground when the contact member 4 is closed.

5 is the red stop lamp in parallel relation to which is arranged the short-circuit'ing circuit 6 with the contact member 7. When the contact member 7 is open this lamp 5 receives -currentfrom the transformer across line9 and ground. If, on the other hand, the contact member lu'strated in the drawing, the current. from are lighted of the common switch control,

d the switch 8 sist'or -1( may 7 is closed, as ilv and in Germany much 28,1924.

the transformer flows across the shunt 6 so that the lamp 5 is extinguished. The two contact members 4 and7 may be arranged upon a common contact lever so that when closing the circuit for the green go ahead lamp 1 the red stop lamp 5 is simultaneously short-circuited. In Fig. 1 I have illustrated the mechanical coaction of both contact levers in conventional manner by the hand lever and link -interconnection 11, 12, 12, by which both contacts may be simultaneously closed and opened. The opening and closing the contact member 7 may also be made inductively dependent upon the go ahead circuit so that, for instance, when the line 3 is traversed by a current the contact member 7 is closed by a relay in the line 3. This feature is illustrated in-Fig. 2 in which 1 3 signifies the relay located in line 3. When this line is closed to actuate signal lamp 1, relay 13 is energized and by attracting its armature operates link sys-' tem 14 which in turn closes switch member 7 and thus establishes a short circuit around danger lamp 5. Spring 15 normally tends to keep switch 7 open. The closing of the stop circuit thus dependsin this case upon the opening of a contact member so that a considerably greater safety is ensured than if the circuit for the red ducted through a closed contact member. In order to avoid the source of current 8 being short-circuited when the lamp 5. is shortcircuited across the line 6 and the contact member 7, a damping resistor 10 is arranged between the red lamp 5 and the source 0 current 8 which resistor prevents a detrimental reaction upon the transformer.

' If the closing of the contact members of 7 and the bridging over or shunting of the red lamp 5 is not brought about while the green lamp is in circuit both lamps 1 and 5 light up together and thus automatically announce the disturbance in the system. The system is equally well applicable for direct as well as for alternating current. The resistanceo f. the resistor 10 may thus be a purely ohmic resistance or also an inductive oreapacitive one. In case of a supply of alternating current the rebe saved by employing as atransform'er with a' large source of current '7 amount of leakage so that when short-circuiting the secondary detrimental reactions lamp were conupon the transformer cannot be developed.

Instead of the single signal lamp a plurality of lamps may be connected in parallel relation in known manner.

Various modifications and changes may be made without departing from the spirit and scope of the invention, I desire therefore that only such limitations shall be placed thereon as are imposed by the prior art.

I claim as my invention In a signal system of the character described, the combination of a current source, a blocking signal lamp connected to said source and a clear track signal lamp connected with said source independently of the blocking lamp, a short circuit connection in shunt to said blocking lamp for completely extinguishing said lamp, said slnmt containing a contact-switch for controlling it, a contact switch in said clear track lamp circuit for interrupting its connection with said s0urce,'means controlled by the operation of said clear track switch for simultaneously closing said shunt switch with said clear track switch, and means in said blocking lamp circuit for preventing a short circuit of said source when said lamp is extinguished. r

In testimony whereof I alfix my signature.

HERMANN ARNDT. 

